Haryana BSEH Secondary NSQF Automotive flashcards
Haryana BSEH Secondary NSQF Automotive · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Fire extinguisher for petrol fire
- A Class B fire involves flammable liquids such as petrol. Use CO2 or dry powder, never water, because water spreads burning fuel and can splash it onto the operator.
- Carbon monoxide hazard in workshop
- Carbon monoxide is odourless, colourless and poisonous because it binds haemoglobin far more strongly than oxygen. Never run an engine in a closed workshop without extraction and a CO detector.
- Jack stand purpose
- A jack only lifts the vehicle. Jack stands are placed under rated chassis points to support it before any part of the body goes under, with wheels on the ground chocked.
- Torque wrench formula
- Torque equals force multiplied by lever length, T = F × L. A force of 150 N at a 0.4 m handle gives 60 N·m, which is the value set on the wrench.
- Micrometer least count
- Least count equals screw pitch divided by thimble divisions. A 0.5 mm pitch screw with 50 thimble divisions reads 0.01 mm per division on the thimble.
- Vernier calliper least count
- Least count equals the smallest main-scale division divided by the number of vernier divisions. A 1 mm main scale with 50 vernier divisions gives 0.02 mm resolution.
- Six-point versus twelve-point socket
- A six-point socket contacts more of each hex flat and resists rounding on tight fasteners. A twelve-point socket engages at more angles for speed but grips less area.
- Compression ratio formula
- Compression ratio equals swept volume plus clearance volume, divided by clearance volume. A 450 cm³ swept volume with 50 cm³ clearance gives 10:1.
- Four-stroke cycle rotations
- One complete four-stroke cycle needs two crankshaft revolutions and one camshaft revolution, with intake, compression, power and exhaust strokes in that order.
- Valve clearance too tight
- Insufficient valve clearance holds the valve slightly off its seat during compression and power, causing gas leakage, overheating and burnt valves, plus poor compression.
- Engine capacity calculation
- Capacity equals number of cylinders × (π/4) × bore² × stroke. With bore and stroke in centimetres the result is in cubic centimetres, the usual engine size figure.
- Clutch free play effect
- Free play is the gap between release bearing and pressure-plate fingers. Too little free play lets the bearing ride the fingers and causes slip; too much prevents full disengagement.
- Torque converter stall speed
- Stall speed is the maximum engine speed reached with the transmission in drive, the output held stationary and the throttle fully open, limited by converter fluid coupling.
- Final drive ratio meaning
- Final drive ratio is ring gear teeth divided by pinion teeth. A higher numeric ratio gives more torque multiplication and acceleration but lower top speed for the same engine speed.
- CV joint boot damage symptom
- A torn constant-velocity joint boot loses grease and admits grit. The joint then clicks or knocks, most noticeable on full-lock turns, and fails if not replaced.
- Brake fluid hygroscopic property
- Glycol brake fluid absorbs moisture from air over time, which lowers its boiling point and can cause vapour lock and fade under heavy braking, so it is tested and replaced periodically.
- Caster angle function
- Caster is the tilt of the steering axis from vertical. Positive caster makes the steering self-centring and stable at speed but increases steering effort.
- MacPherson strut layout
- A MacPherson strut combines coil spring, damper and upper pivot in one unit, saving space and weight, and is common on independent front suspension of small cars.
- Ohm's law statement
- Ohm's law states V = I × R, where V is volts, I is amperes and R is ohms. Power is P = V × I, so a 12 V circuit drawing 5 A uses 60 W.
- Series and parallel resistance
- In series, resistances add and current is common. In parallel, voltage is common and total resistance is less than the smallest branch, because current has more paths.
- Fuse rating purpose
- A fuse protects the wiring from overheating, not the device. It must be replaced with the same rating, and a repeated blow means the fault must be found.
- Battery ampere-hour rating
- Ampere-hour capacity is current multiplied by discharge time. A 60 Ah battery can supply about 3 A for 20 hours at its rated discharge rate before reaching cut-off voltage.
- Stoichiometric air-fuel ratio
- For petrol the chemically correct mass ratio is about 14.7 parts air to 1 part fuel. Richer mixtures use more fuel; leaner mixtures risk higher combustion temperature.
- Oil grade 10W-40 meaning
- The 10W figure describes cold-flow behaviour, the lower the better for cold starts. The 40 figure describes thickness at operating temperature, so one oil covers both conditions.
- Radiator cap pressure effect
- A pressure cap raises coolant boiling point, roughly 3 °C for every 10 kPa above atmospheric. This lets the engine run hotter without boiling and reduces coolant loss.
- Tyre tread wear limit
- Car tyre tread must be at least 1.6 mm in the central three-quarters around the circumference. Tread wear indicator bars in the grooves show when the limit is reached.
- Cold tyre pressure rule
- Tyre pressure is set with cold tyres. Running raises pressure by roughly 0.1 bar per 10 °C, so a hot reading must never be used to set or judge pressure.
- Battery open-circuit voltage
- A fully charged 12 V lead-acid battery rests near 12.6 to 12.8 V. About 12.4 V suggests partial charge and 12.0 V or lower suggests a discharged battery.
- Galvanic corrosion cause
- Two dissimilar metals in contact with an electrolyte form a galvanic cell, and the less noble metal corrodes. Aluminium against steel corrodes the aluminium, so insulation is used.
- Annealing heat treatment
- Annealing heats metal and cools it slowly to soften it, relieve internal stress and improve machinability. It is used after welding or cold working to restore ductility.
- Break-even quantity formula
- Break-even quantity equals fixed costs divided by selling price per unit minus variable cost per unit. Selling below that quantity produces a loss for the period.
- STAR interview answer method
- STAR stands for Situation, Task, Action, Result. The candidate describes a real work situation, the task, the action taken and the measurable outcome achieved.